Subsonic, Transonic, and Supersonic Ground Effect Aerodynamics of an Airfoil

The near-ground flight of new-generation aerospace vehicles—such as horizontally launched electromagnetic systems and sea-skimming missiles—requires a comprehensive understanding of high-speed ground effect (GE) aerodynamics. However, transonic and supersonic GE are far less studied than the subsonic regime. This work systematically examines GE aerodynamics of a representative airfoil across subsonic, transonic and supersonic regimes and a wide range of flight heights by numerically solving the compressible Reynolds-Averaged Navier–Stokes equations. The evolution of flow patterns and aerodynamic characteristics with Mach number in GE is provided to complement classical textbooks focusing on unbounded flows. Relative to subsonic GE, aerodynamic force variations in the transonic and supersonic regimes are substantially larger. The conventional critical height criterion of [Formula: see text] becomes invalid at higher Mach numbers, where significant GE persists even at elevated heights. As the height decreases, the lower critical Mach number increases slightly, whereas the upper critical Mach number rises sharply. Across all regimes, the total lift is primarily governed by pressure changes on the lower surface, although the dominant mechanisms differ: in the subsonic regime, the blocking and camber effects prevail, whereas in the transonic and supersonic regimes, the complex shock-ground interactions are the principal contributors.